Authorisation

Before you indulge into an experiment investigating the effects of whatever quality of a subject, it is the best for you to make sure beforehand that the quality in question does belong to your subject.

We colloquially say: «a red pencil» as if it is not a question whether a pencil can be red. Indeed, it can. In this particular case our «intuition» coincide with physical reality. We can create an experiment that demonstrates a possibility of any colour be a quality of a pencil. We can clearly define «red» as a specific feature of the light spectrum, and we can unambiguously link those spectra to each pencil. We can see (experimentally) that some pencils share this quality, while some do not. Even if the dividing line between these sets is fuzzy, we now have a CHARACTERISTIC PROPERTY of a «red pencil»: all red pencils share this property, and all non red do not have it. Facing a pencil, we can (experimentally) determine if it is red (and to what extent).

It is perfectly legitimate for anyone to call a pencil «red» or otherwise tag a pencil with a colour, because of the physics, not because the language allows it. Language is equally suitable for describing reality and nonsense as well. We still can call a pencil «aggressive» but it does not make physical sense. Aggressiveness can not be observed in pencils. There are many qualities applicable to pencils and there are many qualities inapplicable to pencils. Some qualities are plainly inapplicable to some objects — this fact is so basic that is often forgotten.

Now, I give you two grains of wheat, one is «GMO» and another isn't.
Can you conceive an experiment that tells me which is which?

Maybe it is time to make one step back and determine if «GMO» is a quality of an organism? Is there any CHARACTERISTIC PROPERTY of a «GM organism», something that all «GM» subjects share, while none of the rest have? Please, define this property for me. ...or simply ask yourself (every time you are looking for the magical label on the food package) what is this characteristic property I am looking for?

Now, as you have yelled at me all your suggestions, think carefully which of them is actually a property of an organism. Not single one. All that you have come up with are qualities of a production process or a design process or even earlier. None of those can be observed in a grain of wheat.

Observing a car, can you tell, for example, a difference between a car that was sketched with HB pencil and a car sketched with 2B pencil during their stage of development? In case of a car you would not claim that all qualities of a design phase are inherited by the product. You may consider me foolish to even suggest this very possibility. It is too obvious for you that a car and a car production process are two wildly different objects. Ok, then. What makes you claim that «GM» property of an organism design process is also a quality of a resulted organism? Hopefully you are not going to claim that organisms and their production processes are the same object.

However, you may legitimately conjecture that this particular property somehow translates from the design process to the organism. This is why I gave you these two grains of wheat. Take them and prove your conjecture. Show me the CHARACTERISTIC PROPERTY of «GMO».

I know you are wondering what all this nonsense has to do with passwords.
Well, this is all about the information entropy, which you do happily assign to your passwords without even a glimpse of doubt: IS IT REALLY A QUALITY OF A PASSWORD??? CAN I CREATE A CHARACTERISTIC RELATION THAT MAPS PASSWORDS ON REAL NUMBERS AND IS A FUNCTION???

I have a strong conviction that 99% of «security experts» do not know the definition of the entropy. This conviction does certainly seem wildly deranged for you, unless you know the definition in question. So, let's begin with the definition, by the book.
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It turned out that my "Authentication vs Identification" article was not sufficiently conclusive in the sense that some hardcore biometrics fans still nurture a non-trivial and well justified objection. So I need to address and destroy it, in order to close the topic. My opponents' argument is:

Your analysis narrows the both sides of the problem to a knowledge/ownership claim. Even if you are right, the conclusion is only applicable to the authentication by means of a knowledge token, whereas all the rest relations between the user and the token (suitable for authentication purposes) are set aside. There is one particularly important relation (the one fundamental for the entire biometrics field): «the user is» or other way around «the token is a part of the user» — this relation implies inalienability which makes the token safe for authentication purposes.

It is true. Completely true. It is undeniably true! In the physical realm.
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Once again I have to return to the topic of strict antagonism between the authentication and the identification, meaning these very processes and the tokens involved as well. Before I indulge into boring you with tedious decomposition of entities you used to perceive as atomic, I present you a synthetic illustration of the difference in question. A bad guy tries to get a false-negative outcome of identification, and a false-positive outcome of authentication. This is not explanatory, yet very indicative, I hope it gives you an idea of the magnitude of the difference, and we are going to dig into this now.
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Simple questions are usually the most difficult ones to answer. And the most important among them are traditionally labeled stupid and dismissed. The modern days InfoSec is based upon unanswered questions. The lack of theoretical basis allows InfoSec gurus to produce teachings and «best practices» without a limit.

Today I want to address two very basic questions about passwords:

What are characteristic properties of a password? and what makes your password yours?

By answering these questions you achieve understanding of the utter malevolence of the password abandonment movements, that are so frighteningly popular today. There is a particularly dangerous movement to replace passwords with bio-metric attributes that can reliably identify your body (e.g. voice, fingerprints, and such). Although these attributes are successfully used in forensic practice for centuries, it does not make them good authentication tokens. Why? Because your password's job is NOT to identify your body.

I hear you screaming: «WHAT?!?!?!» That means you are ready to investigate what IS a password, what is its job, and what properties do you want your password to possess.
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I suggested in the article to use passphrases instead of «traditional» passwords, for multiple reasons, including: sheer strength, memorability, and conforming to idiotic password creation policies without actually following detrimental recommendations of the policy authors.

This recommendation gives rise to a reasonable doubt: «what if syntactically correct phrases are as weak as dictionary words in comparison to a random string of symbols?''. Indeed, syntax itself should weaken a passphrase, as it provides some „predictability'' to the phrase. I want to address this problem, by comparing syntactically correct passphrases to random collections of words (which we all consider sufficiently strong… hopefully).
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It is also worth noticing that Shannon's entropy is entirely irrelevant to the password strength problem. Entropy is based on the ASSUMPTION of possible outcomes. This set is well defined in the context of measuring a memory size, and not defined at all in the context of password creation/guessing.

In contrast to my work, the «password strength» discourse is extraordinarily rich on bullshit. Take a look at this masterpiece. This is a great example of how to write some 35K of text without answering the question, and even without understanding the subject. Let me quote the key paragraph:

Password strength is a measure of the effectiveness of a password in resisting guessing and brute-force attacks. In its usual form, it estimates how many trials an attacker who does not have direct access to the password would need, on average, to guess it correctly. The strength of a password is a function of length, complexity, and unpredictability.

This is one of the best non-answers I have ever seen, and a very succinct one too. No wonder it originates from the government officials! It obscures the matter it addresses in almost every word — «effectiveness», «resisting», «complexity», «unpredictability» — what are they? So, essentially the quoted paragraph reads:

Password strength is a function of something unknown to us.

It is time for us to do some trivial maths and terminate the «password strength» nonsense.